Plasma interleukin-5 levels are related to antibodies binding to oxidized low-density lipoprotein and to decreased subclinical atherosclerosis.
OBJECTIVE
This study's aim was to assess the role of interleukin (IL)-5 in modulating the levels of antibodies binding to oxidized low-density lipoprotein (OxLDL) in human atherosclerosis.


BACKGROUND
Various pro- and anti-inflammatory cytokines have been implicated in atherogenesis, and recent findings in mice indicate that the cytokine IL-5 plays a protective role in atherosclerosis in part via the induction of antibodies binding to OxLDL.


METHODS
Plasma IL-5 levels and antibody titers to 2 most commonly used models of OxLDL (copper OxLDL and malondialdehyde-modified LDL) were measured in 1,011 Finnish middle-aged subjects with chemiluminescent enzyme-linked immunosorbent assay. Intima-media thickness (IMT) was assessed ultrasonographically from the internal carotid artery, the bifurcation, and the common carotid artery.


RESULTS
There was a significant positive association between plasma IL-5 levels and antibody titers to copper OxLDL (p = 0.010 and p = 0.044, immunoglobin [Ig] M and G, respectively) and IgM to malondialdehyde-modified LDL (p < 0.001) in the association analysis performed between different IL-5 quartiles. Furthermore, plasma IL-5 levels were found to be inversely associated with bifurcational IMT, and even after adjustments for traditional risk factors of atherosclerosis (age, gender, smoking, systolic blood pressure, LDL, and body mass index), IL-5 remained an independent determinant of the mean bifurcational IMT (p = 0.010).


CONCLUSIONS
Our data demonstrate that plasma IL-5 levels are related to the plasma levels of antibodies binding to OxLDL and to decreased subclinical atherosclerosis in humans. These results are in line with earlier findings in murine atherosclerosis and indicate for the first time that IL-5 may play a role in human atherosclerosis.
Sämpi
Maritta
M
Department of Internal Medicine, Biocenter Oulu, Oulu, Finland.
Ukkola
Olavi
O
Päivänsalo
Markku
M
Kesäniemi
Y Antero
YA
Binder
Christoph J
CJ
Hörkkö
Sohvi
S
D000328:Adult; D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D002340:Carotid Artery Diseases / Q000097:blood* / Q000276:immunology; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000276:immunology; D005260:Female; D005387:Finland; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D015848:Interleukin-5 / Q000097:blood*; D008077:Lipoproteins, LDL / Q000097:blood* / Q000276:immunology; D008297:Male; D051379:Mice; D008875:Middle Aged; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000276:immunology; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000276:immunology; D014463:Ultrasonography
D001323:Autoantibodies; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015848:Interleukin-5; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein